US10938398B2 - Analog-to-digital converter and microphone including the same - Google Patents
Analog-to-digital converter and microphone including the same Download PDFInfo
- Publication number
- US10938398B2 US10938398B2 US16/790,598 US202016790598A US10938398B2 US 10938398 B2 US10938398 B2 US 10938398B2 US 202016790598 A US202016790598 A US 202016790598A US 10938398 B2 US10938398 B2 US 10938398B2
- Authority
- US
- United States
- Prior art keywords
- output
- signal
- analog
- digital
- operator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000005236 sound signal Effects 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 7
- 238000001914 filtration Methods 0.000 description 6
- 239000003990 capacitor Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000013139 quantization Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/001—Analogue/digital/analogue conversion
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/06—Continuously compensating for, or preventing, undesired influence of physical parameters
- H03M1/0617—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence
- H03M1/0626—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by filtering
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/12—Analogue/digital converters
- H03M1/124—Sampling or signal conditioning arrangements specially adapted for A/D converters
- H03M1/129—Means for adapting the input signal to the range the converter can handle, e.g. limiting, pre-scaling ; Out-of-range indication
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/12—Analogue/digital converters
- H03M1/18—Automatic control for modifying the range of signals the converter can handle, e.g. gain ranging
- H03M1/181—Automatic control for modifying the range of signals the converter can handle, e.g. gain ranging in feedback mode, i.e. by determining the range to be selected from one or more previous digital output values
- H03M1/183—Automatic control for modifying the range of signals the converter can handle, e.g. gain ranging in feedback mode, i.e. by determining the range to be selected from one or more previous digital output values the feedback signal controlling the gain of an amplifier or attenuator preceding the analogue/digital converter
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/12—Analogue/digital converters
- H03M1/34—Analogue value compared with reference values
- H03M1/38—Analogue value compared with reference values sequentially only, e.g. successive approximation type
- H03M1/42—Sequential comparisons in series-connected stages with no change in value of analogue signal
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R19/00—Electrostatic transducers
- H04R19/04—Microphones
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/002—Provisions or arrangements for saving power, e.g. by allowing a sleep mode, using lower supply voltage for downstream stages, using multiple clock domains or by selectively turning on stages when needed
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M3/00—Conversion of analogue values to or from differential modulation
- H03M3/30—Delta-sigma modulation
- H03M3/322—Continuously compensating for, or preventing, undesired influence of physical parameters
- H03M3/324—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by means or methods for compensating or preventing more than one type of error at a time, e.g. by synchronisation or using a ratiometric arrangement
- H03M3/346—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by means or methods for compensating or preventing more than one type of error at a time, e.g. by synchronisation or using a ratiometric arrangement by suppressing active signals at predetermined times, e.g. muting, using non-overlapping clock phases
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M3/00—Conversion of analogue values to or from differential modulation
- H03M3/30—Delta-sigma modulation
- H03M3/39—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators
- H03M3/412—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators characterised by the number of quantisers and their type and resolution
- H03M3/422—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators characterised by the number of quantisers and their type and resolution having one quantiser only
- H03M3/424—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators characterised by the number of quantisers and their type and resolution having one quantiser only the quantiser being a multiple bit one
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
- H04R2201/003—Mems transducers or their use
Definitions
- Various embodiments generally relate to an analog-to-digital converter (ADC) and a microphone including the ADC.
- ADC analog-to-digital converter
- FIG. 1 shows an ADC 10 and a microphone 1 including the ADC 10 according to a conventional art.
- the conventional microphone 1 includes a MEMS device 20 and the ADC 10 for converting an output of the MEMS device 20 into a digital signal.
- the MEMS device 20 outputs an electrical signal corresponding to a sound signal IN.
- the ADC 10 outputs a digital signal OUT corresponding to the electrical signal output from the MEMS device 20 .
- the ADC 10 uses a sigma-delta modulation scheme.
- the ADC 10 includes an amplifier 11 for amplifying an output of the MEMS device 20 , an operator 12 for subtracting an output of the digital-to-analog converter (DAC) 15 from an output of the amplifier 11 , and a filter 13 for filtering an output of the operator 12 , a quantizer 14 for converting an output of the filter 13 to a digital bit stream, a DAC 15 for converting the digital bit stream to an analog value, and a decimator 16 for converting the digital bit stream into the digital signal OUT.
- DAC digital-to-analog converter
- the amplifier 11 may be implemented using a source follower or a charge amplifier.
- the output of the MEMS device 20 is amplified by the amplifier 11 , but the output of the amplifier 11 cannot be out of the range of the power supply voltage.
- This distortion of the signal causes a problem that harmonic components of the output signal increases, which degrades signal quality.
- an analog-to-digital converter may include a first operator configured to subtract an analog value from an analog signal; an amplifier configured to amplify an output of the first selector; a filter configured to filter an output of the amplifier; a quantizer configured to generate a digital bit stream from an output of the filter; and a digital-to-analog converter (DAC) configured to output the analog value according to the digital bit stream.
- ADC analog-to-digital converter
- an analog-to-digital converter may include a first operator configured to subtract an analog value from an analog signal; a detector configured to output a selection signal according to magnitude of the analog signal; a first selector configured to select the analog signal or an output of the first operator according to the selection signal; an amplifier configured to amplify an output of the first selector; a second operator configured to subtract the analog value from an output signal from the amplifier; a second selector configured to select the output of the amplifier or an output of the second operator according to the selection signal; a filter configured to filter an output of the second selector; a quantizer configured to generate a digital bit stream from an output of the filter; and a digital-to-analog converter (DAC) configured to output the analog value according to the digital bit stream.
- ADC analog-to-digital converter
- a microphone may include a MEMS device configured to output an analog signal from a sound signal; and an analog-to-digital converter (ADC) configured to output a digital signal from the analog signal, wherein the ADC comprises a first operator configured to subtract an analog value from the analog signal; a detector configured to output a selection signal according to magnitude of the analog signal; a first selector configured to select the analog signal or an output of the first operator according to the selection signal; an amplifier configured to amplify an output of the first selector; a second operator configured to subtract the analog value from an output signal from the amplifier; a second selector configured to select the output of the amplifier or an output of the second operator according to the selection signal; a filter configured to filter an output of the second selector; a quantizer configured to generate a digital bit stream from an output of the filter; and a digital-to-analog converter (DAC) configured to output the analog value according to the digital bit stream.
- ADC analog-to-digital converter
- FIG. 1 shows a block diagram of an analog-to-digital converter (ADC) and a microphone including the ADC according to a prior art.
- ADC analog-to-digital converter
- FIG. 2 shows a block diagram of an ADC and a microphone including the ADC according to an embodiment of the present disclosure.
- FIG. 3 shows a block diagram of an ADC and a microphone including the ADC according to an embodiment of the present disclosure.
- FIG. 4 shows a block diagram of a detector according to an embodiment of the present disclosure.
- FIG. 5 shows a graph illustrating effect of an embodiment of the present disclosure.
- FIG. 2 is a block diagram of an analog-to-digital converter (ADC) 100 and a microphone 1000 including the ADC 100 according to an embodiment of the present disclosure.
- ADC analog-to-digital converter
- the MEMS device 20 outputs an electrical signal corresponding to the sound signal IN.
- the ADC 100 outputs a digital signal OUT corresponding to the electrical signal output from the MEMS device 20 .
- the ADC 100 includes a sigma-delta modulator.
- the ADC 100 includes an operator 120 for subtracting an output of a digital-to-analog converter (DAC) 150 from the output of the MEMS device 20 , an amplifier 110 for amplifying an output of the operator 120 , a filter 130 for filtering an output of the amplifier 110 , a quantizer 140 for converting an output of the filter 130 into a digital bit stream, the DAC 150 for converting the digital bit stream into an analog value such as an analog voltage, and a decimator 160 for converting the digital bit stream into the digital signal OUT.
- DAC digital-to-analog converter
- the amplifier 110 amplifies the output of the operator 120 rather than the output of the MEMS device 20 .
- the output of the operator 120 corresponds to quantization noise, so the amplitude thereof is very small.
- Amplifier 110 may be implemented using a source follower or a charge amplifier.
- the operator 120 may be implemented in a manner further including a capacitor for converting the analog voltage into a charge amount.
- an ADC 100 may be set to function as in FIG. 2 when the signal output from the MEMS device 20 exceeds a predetermined level.
- FIG. 3 is a block diagram of an ADC 200 and a microphone 2000 including the ADC 200 according to an embodiment of the present disclosure.
- the ADC 200 includes a first amplifier 221 for subtracting an output of a DAC 250 from an output of the MEMS device 20 , an amplifier 210 for amplifying an output of a first selector 281 , a second operator 222 for subtracting the output of a DAC 250 from an output of the amplifier 210 , a filter for filtering an output of a second selector 282 , a quantizer 240 for converting an output of the filter 230 into a digital bit stream, the DAC 250 for converting the digital bit stream to an analog value such as an analog voltage, and a decimator 260 for converting the digital bit stream into a digital signal OUT.
- the ADC 200 further includes the first operator 281 that selects the output of the MEMS device 20 when the selection signal SEL is logic 0, and selects the output of the first operator 221 when the selection signal SEL is logic 1.
- the ADC 200 further includes the second selector 282 that selects the output of the amplifier 210 when the selection signal SEL is logic 1, and selects the output of the second operator 222 when the selection signal SEL is logic 0.
- the ADC 200 further includes a detector 270 that outputs the selection signal SEL.
- the detector 270 determines whether the output of the MEMS device 20 is equal to or less than a predetermined value.
- the detector 270 determines whether the digital signal OUT corresponding to the output signal of the MEMS device 20 is less than or equal to a threshold value.
- the selection signal SEL becomes a signal of logic 0 when the magnitude of the digital signal OUT is equal to or less than the threshold value and becomes a signal of logic 1 otherwise.
- the first selector 281 selects the output of the MEMS device 20
- the second selector 282 selects the output of the second operator 222 .
- the ADC 200 when the magnitude of the digital signal OUT is less than or equal to the threshold value, the ADC 200 operates like the conventional ADC 10 of FIG. 1 .
- the first selector 281 selects the output of the first operator 221
- the second selector 282 selects the output of the amplifier 210 .
- the ADC 200 when the magnitude of the digital signal OUT is greater than the threshold value, the ADC 200 operates like the ADC 100 of FIG. 2 .
- the first operator 221 may comprise a capacitor for converting the analog voltage from the DAC 250 into charge amount like the operator 120 included in the embodiment illustrated in FIG. 2 .
- the detector 270 detects the magnitude of the digital signal OUT output from the decimator 260 and outputs a selection signal SEL.
- FIG. 4 shows a block diagram illustrating the detector 270 according to an embodiment of the present disclosure.
- the detector 270 includes a converting circuit 271 and a comparator 272 .
- the converting circuit 271 outputs an amplitude signal having a value corresponding to the amplitude of the digital signal OUT.
- the graph of FIG. 4 is shown as a continuous graph, which approximates discrete signals extracted from the digital signal OUT.
- the comparator 272 performs a low-pass filtering on the amplitude signal and compares a result of the low-pass filtering with the threshold value TH to output a selection signal SEL.
- the selection signal SEL has a logic 0 when the envelope is below the threshold value TH and has a logic 1 when the envelope is above the threshold value TH.
- FIG. 5 shows a graph illustrating effect of an embodiment of the present disclosure.
- the simulation result in FIG. 5 assumes that a signal of a 1.5 KHz sine wave is output from the MEMS device 20 .
- harmonic components corresponding to multiples of 1.5 KHz are generated, but the harmonic components are not generated in the present embodiment.
- the Signal-to-Total-Noise and Distortion Ratio (SNDR) is greatly improved to 111.3 dB in the present embodiment from 33.8 dB in the prior art.
- SFDR Spurious Free Dynamic Range
Landscapes
- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Compression, Expansion, Code Conversion, And Decoders (AREA)
- Analogue/Digital Conversion (AREA)
Abstract
Description
Claims (10)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020170113585A KR101887824B1 (en) | 2017-09-05 | 2017-09-05 | Analog to digital converting device and microphone including the same |
KR10-2017-0113585 | 2017-09-05 | ||
PCT/KR2018/009889 WO2019050204A1 (en) | 2017-09-05 | 2018-08-28 | Analog-to-digital conversion apparatus and microphone including same |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/KR2018/009889 Continuation WO2019050204A1 (en) | 2017-09-05 | 2018-08-28 | Analog-to-digital conversion apparatus and microphone including same |
Publications (2)
Publication Number | Publication Date |
---|---|
US20200186157A1 US20200186157A1 (en) | 2020-06-11 |
US10938398B2 true US10938398B2 (en) | 2021-03-02 |
Family
ID=63229823
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/790,598 Active US10938398B2 (en) | 2017-09-05 | 2020-02-13 | Analog-to-digital converter and microphone including the same |
Country Status (3)
Country | Link |
---|---|
US (1) | US10938398B2 (en) |
KR (1) | KR101887824B1 (en) |
WO (1) | WO2019050204A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR101626876B1 (en) * | 2015-12-17 | 2016-06-02 | 서울대학교 산학협력단 | Beamforming device and system including the same |
US12069430B2 (en) | 2021-03-03 | 2024-08-20 | Invensense, Inc. | Microphone with flexible performance |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20040111385A (en) | 2002-03-07 | 2004-12-31 | 자링크 세미컨덕터 에이비 | Digital microphone |
US20060097899A1 (en) | 2004-11-10 | 2006-05-11 | Fujitsu Limited | Adaptive-type sigma-delta a/d converter |
KR100925397B1 (en) | 2007-09-12 | 2009-11-09 | 지씨티 세미컨덕터 인코포레이티드 | Effective loop filter for a continuous time sigma delta analog to digital converter |
KR20130092479A (en) | 2012-02-10 | 2013-08-20 | 인피니언 테크놀로지스 아게 | System and method for a pcm interface for a capacitive signal source |
US20140250971A1 (en) | 2013-03-08 | 2014-09-11 | Freescale Semiconductor, Inc. | System and method for monitoring an accelerometer |
US9100032B2 (en) * | 2013-08-08 | 2015-08-04 | Infineon Technologies Ag | Methods and devices for analog-to-digital conversion |
US20160097899A1 (en) | 2013-03-26 | 2016-04-07 | Lumentum Operations Llc | Packaging an arcuate planar lightwave circuit |
US9356567B2 (en) * | 2013-03-08 | 2016-05-31 | Invensense, Inc. | Integrated audio amplification circuit with multi-functional external terminals |
KR20160117590A (en) | 2014-02-05 | 2016-10-10 | 로베르트 보쉬 게엠베하 | Method and means for regulating the electrical bias voltage in the measuring capacitor of a mems sensor element |
KR101738266B1 (en) | 2014-10-17 | 2017-05-19 | 인피니언 테크놀로지스 아게 | Very high dynamic-range switched capacitor adc with large input impedance for applications tolerating increased distortion and noise at large input signal levels |
-
2017
- 2017-09-05 KR KR1020170113585A patent/KR101887824B1/en active IP Right Grant
-
2018
- 2018-08-28 WO PCT/KR2018/009889 patent/WO2019050204A1/en active Application Filing
-
2020
- 2020-02-13 US US16/790,598 patent/US10938398B2/en active Active
Patent Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20040111385A (en) | 2002-03-07 | 2004-12-31 | 자링크 세미컨덕터 에이비 | Digital microphone |
US20060097899A1 (en) | 2004-11-10 | 2006-05-11 | Fujitsu Limited | Adaptive-type sigma-delta a/d converter |
KR100925397B1 (en) | 2007-09-12 | 2009-11-09 | 지씨티 세미컨덕터 인코포레이티드 | Effective loop filter for a continuous time sigma delta analog to digital converter |
KR20130092479A (en) | 2012-02-10 | 2013-08-20 | 인피니언 테크놀로지스 아게 | System and method for a pcm interface for a capacitive signal source |
US20140250971A1 (en) | 2013-03-08 | 2014-09-11 | Freescale Semiconductor, Inc. | System and method for monitoring an accelerometer |
US9297826B2 (en) | 2013-03-08 | 2016-03-29 | Freescale Semiconductor Inc. | System and method for monitoring an accelerometer |
US9356567B2 (en) * | 2013-03-08 | 2016-05-31 | Invensense, Inc. | Integrated audio amplification circuit with multi-functional external terminals |
US20160097899A1 (en) | 2013-03-26 | 2016-04-07 | Lumentum Operations Llc | Packaging an arcuate planar lightwave circuit |
US9100032B2 (en) * | 2013-08-08 | 2015-08-04 | Infineon Technologies Ag | Methods and devices for analog-to-digital conversion |
KR20160117590A (en) | 2014-02-05 | 2016-10-10 | 로베르트 보쉬 게엠베하 | Method and means for regulating the electrical bias voltage in the measuring capacitor of a mems sensor element |
KR101738266B1 (en) | 2014-10-17 | 2017-05-19 | 인피니언 테크놀로지스 아게 | Very high dynamic-range switched capacitor adc with large input impedance for applications tolerating increased distortion and noise at large input signal levels |
Also Published As
Publication number | Publication date |
---|---|
US20200186157A1 (en) | 2020-06-11 |
KR101887824B1 (en) | 2018-08-10 |
WO2019050204A1 (en) | 2019-03-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US9407224B2 (en) | Digital microphone device with extended dynamic range | |
JP6295208B2 (en) | Digital input class D audio amplifier | |
US10938398B2 (en) | Analog-to-digital converter and microphone including the same | |
US9100032B2 (en) | Methods and devices for analog-to-digital conversion | |
US9693138B2 (en) | Audio speaker protection system and method | |
US7345606B2 (en) | DA-converter system and a method for converting a multi-bit digital signal to an analog signal | |
US10084474B1 (en) | Noise shaping circuit and sigma-delta digital-to-analog converter | |
US10200051B2 (en) | Analog-to-digital converter with an increased resolution first stage | |
US7333041B2 (en) | System for analog-to-digital conversion | |
US8890735B2 (en) | Multi-level sigma-delta ADC with reduced quantization levels | |
US8487792B2 (en) | Method of gain calibration of an ADC stage and an ADC stage | |
WO2022069852A1 (en) | Analog-to-digital converter and method | |
CN111587532B (en) | sensor device | |
US20170288690A1 (en) | Adaptive configuration to achieve low noise and low distortion in an analog system | |
KR20180041171A (en) | Phase shorting switch | |
US9172494B2 (en) | Modulator device | |
US10840869B2 (en) | Capacitive MEMS microphone with active compression | |
US11183975B2 (en) | Window based supply voltage conditioning circuit for noise filtering | |
US11025269B2 (en) | Capacitively coupled continuous-time delta-sigma modulator and operation method thereof | |
CN101120507A (en) | AD converter arrangement | |
US20230243877A1 (en) | Impedance controlled afe | |
US11916563B2 (en) | Analog-to-digital converter, sensor processing circuit, and sensor system | |
KR101812924B1 (en) | Analog to digital converting device and system including the same | |
US20180335458A1 (en) | Capacitance sensor | |
KR20140014455A (en) | Continuous time sigma-delta analog to digital converter with circuit stabilization function |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION, KOREA, REPUBLIC OF Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KIM, SUHWAN;CHO, JUNSOO;YANG, YOUNGTAE;REEL/FRAME:051817/0221 Effective date: 20200212 |
|
FEPP | Fee payment procedure |
Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT VERIFIED |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FEPP | Fee payment procedure |
Free format text: ENTITY STATUS SET TO SMALL (ORIGINAL EVENT CODE: SMAL); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YR, SMALL ENTITY (ORIGINAL EVENT CODE: M2551); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY Year of fee payment: 4 |